Coal pressurization and feeding: Use of a lock hopper system

Operation of a synthane gasifier pilot plant is discussed. The specific problems experienced with the operation of the Petrocarb system at the pilot plant are described along with modifications made to improve its performance

Penetration depth for shallow impact cratering

We present data for the penetration of a variety of spheres, dropped from rest, into a level non-cohesive granular medium. We improve upon our earlier work [Uehara {\it et al.} Phys. Rev. Lett. {\bf 90}, 194301 (2003)] in three regards. First, we explore the behavior vs sphere diameter and density more systematically, by holding one of these parameters constant while varying the other. Second, we prepare the granular medium more reproducibly and, third, we measure the penetration depth more accurately. The new data support our previous conclusion that the penetration depth is proportional to the 1/2 power of sphere density, the 2/3 power of sphere diameter, and the 1/3 power of total drop distance

The Cam-type Deformity of the Proximal Femur Arises in Childhood in Response to Vigorous Sporting Activity

Background: The prevalence of a cam-type deformity in athletes and its association with vigorous sports activities during and after the growth period is unknown. Questions/purposes: We therefore compared the prevalence and occurrence of a cam-type deformity by MRI in athletes during childhood and adolescence with an age-matched control group. Patients and Methods: We retrospectively reviewed 72 hips in 37 male basketball players with a mean age of 17.6years (range, 9-25years) and 76 asymptomatic hips of 38 age-matched volunteers who had not participated in sporting activities at a high level. Results: Eleven (15%) of the 72 hips in the athletes were painful and had positive anterior impingement tests on physical examination. Internal rotation of the hip averaged 30.1° (range, 15°-45°) in the control group compared with only 18.9° (range, 0°-45°) in the athletes. The maximum value of the alpha angle throughout the anterosuperior head segment was larger in the athletes (average, 60.5°±9°), compared with the control group (47.4°±4°). These differences became more pronounced after closure of the capital growth plate. Overall, the athletes had a 10-fold increased likelihood of having an alpha angle greater than 55° at least at one measurement position. Conclusions: Our observations suggest a high intensity of sports activity during adolescence is associated with a substantial increase in the risk of cam-type impingement. These patients also may be at increased risk of subsequent development of secondary coxarthrosis. Level of Evidence: Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidenc

Awareness and use of intertrochanteric osteotomies in current clinical practice. An international survey

Current literature shows that intertrochanteric osteotomies can produce excellent results in selected hip disorders in specific groups of patients. However, it appears that this surgical option is considered an historical one that has no role to play in modern practice. In order to examine current awareness of and views on intertrochanteric osteotomies among international hip surgeons, an online survey was carried out. The survey consisted of a set of questions regarding current clinical practice and awareness of osteotomies. The second part of the survey consisted of five clinical cases and sought to elicit views on preoperative radiological investigations and preferred (surgical) treatments. The results of our survey showed that most of these experts believe that intertrochanteric osteotomies should still be performed in selected cases. Only 56% perform intertrochanteric osteotomies themselves and of those, only 11% perform more than five per year. The responses to the cases show that about 30–40% recommend intertrochanteric osteotomies in young symptomatic patients. This survey shows that the role of intertrochanteric osteotomies is declining in clinical practice

Dry conditions disrupt terrestrial-aquatic linkages in northern catchments.

Aquatic ecosystems depend on terrestrial organic matter (tOM) to regulate many functions, such as food web production and water quality, but an increasing frequency and intensity of drought across northern ecosystems is threatening to disrupt this important connection. Dry conditions reduce tOM export and can also oxidize wetland soils and release stored contaminants into stream flow after rainfall. Here, we test whether these disruptions to terrestrial-aquatic linkages occur during mild summer drought and whether this affects biota across 43 littoral zone sites in 11 lakes. We use copper (Cu) and nickel (Ni) as representative contaminants, and measure abundances of Hyalella azteca, a widespread indicator of ecosystem condition and food web production. We found that tOM concentrations were reduced but correlations with organic soils (wetlands and riparian forests) persisted during mild drought and were sufficient to suppress labile Cu concentrations. Wetlands, however, also became a source of labile Ni to littoral zones, which was linked to reduced abundances of the amphipod H. azteca, on average by up to 70 times across the range of observed Ni concentrations. This reveals a duality in the functional linkage of organic soils to aquatic ecosystems whereby they can help buffer the effects of hydrologic disconnection between catchments and lakes but at the cost of biogeochemical changes that release stored contaminants. As evidence of the toxicity of trace contaminant concentrations and their global dispersion grows, sustaining links among forests, organic soils and aquatic ecosystems in a changing climate will become increasingly important.Natural Environment Research Council (Grant ID: NE/L006561/1)This is the final version of the article. It first appeared from Wiley via https://doi.org/10.1111/gcb.1336

Revisions to the derivation of the Australian and New Zealand guidelines for toxicants in fresh and marine waters

The Australian and New Zealand Guidelines for Fresh and Marine Water Quality are a key document in the Australian National Water Quality Management Strategy. These guidelines released in 2000 are currently being reviewed and updated. The revision is being co-ordinated by the Australian Department of Sustainability, Environment, Water, Population and Communities, while technical matters are dealt with by a series of Working Groups. The revision will be evolutionary in nature reflecting the latest scientific developments and a range of stakeholder desires. Key changes will be: increasing the types and sources of data that can be used; working collaboratively with industry to permit the use of commercial-in-confidence data; increasing the minimum data requirements; including a measure of the uncertainty of the trigger value; improving the software used to calculate trigger values; increasing the rigour of site-specific trigger values; improving the method for assessing the reliability of the trigger values; and providing guidance of measures of toxicity and toxicological endpoints that may, in the near future, be appropriate for trigger value derivation. These changes will markedly improve the number and quality of the trigger values that can be derived and will increase end-users’ ability to understand and implement the guidelines in a scientifically rigorous manner

The impact of nanoscale chemical features on micron-scale adhesion: Crossover from heterogeneity-dominated to mean-field behavior

This work explores the impact of nanoscale surface heterogeneity, small relative to the effective contact area between two surfaces, on pairwise colloid-scale interactions. Polycation-based positive patches, of order 10 nm in diameter, arranged randomly and lying flat on otherwise negative substrates, were used to create surfaces whose competing attractive and repulsive features determined the net interactions with opposing surfaces. Lab experiments and simulations of the adhesion of gently flowing dilute negative microparticles varied particle size (0.5–2 μm), ionic strength (κ−1 = 1–12 nm) and the density of heterogeneity on the collectors. Limiting behaviors from heterogeneity-controlled at high ionic strength to mean-field-like interactions at low ionic strength are reported. When heterogeneities are important, pairwise interactions are more attractive than predicted by average surface properties (e.g. per DLVO), and an adhesion threshold, describing the minimum average density of cationic features needed for single particle capture (adhesion), depends strongly on Debye length. In the opposite limit, the threshold becomes insensitive to the Debye length, and the average surface character approximates the interactions. An analytical treatment, reduced to a simple scaling argument predicts a −1/2 power-law dependence of the adhesion threshold on Debye length and particle size. A slightly stronger particle size dependence in experiments and simulations results from hydrodynamic contributions along with slight scaling differences in electrostatic, van der Waals, and hydrodynamic forces. An analogy to biological ligands is made for the heterogeneity-dominated limit: it is discovered, for this particular system, that engagement of as few as 20–100 cationic patches dictates particle adhesion (with details depending on flow, particle size, and ionic strength), similar to reports for selectin-mediated rolling of white blood cells during the inflammatory pathway. Also discovered is a heterogeneity-dependent crossover in the effect of ionic strength on particle capture, where added salt promotes particle adhesion in most cases but stabilizes the particles when the heterogeneity becomes relatively dense

Using torsional dilatometry to measure the effects of deformations on physical aging

The physical aging of polymer glasses, a phenomenon not completely understood, is an important fundamental topic to the polymer physicist as well as an area of practical concern, since the long-time performance of composites relies on the properties of the matrix, many of which are polymer glasses. Here we present results from our study of an epoxy network (Jeffamine D400/DGEBA, described previously), employing torsional dilatometry to simultaneously measure volume changes and torque relaxation from strains imposed after a quench from 44 to 33.5 C (Tg = 42.4 C). To summarize, in concurrence with the speculations of Struik, we measure volume increases induced by torsion during the slow aging contraction from the quench. The torque relaxation data superpose, but must be shifted farther for tests at 1% strain than those at 3% strain. This does not, however, indicate an erasure of aging on the molecular level, since there is no difference between the ultimate equilibration times based on the evolution of the torque relaxation, in agreement with Lee\u27s data. Further, the sample contraction from the quench is unaltered by subsequent torsional deformations, though these momentarily increase sample volume. The dilatation induced from the torsion relaxes much more rapidly than the slow contraction from the quench. In fact, the equilibration time for volume recovery from the later also exceeds the equilibration time for torque relaxations by at least an order of magnitude, suggesting that the mechanical properties and volume changes are affected differently by physical aging

Implications of pH manipulation methods for metal toxicity: Not all acidic environments are created equal

The toxicity of many metals is impacted by environmental pH, through both competition and complexation by hydroxide and carbonate ions. To establish safe environmental regulation it is important to properly define the relationship between pH and metal toxicity, a process that involves manipulating the pH of test water in the lab. The current study compares the effects of the three most common pH manipulation methods (carbon dioxide, acid–base addition, and chemical buffers) on acute Pb toxicity of a model fish species, Pimephales promelas. Acidification of test water revealed that the Pb and Pb2+ LC50 values were impacted by the pH manipulation method, with the following order of effects: HCl<CO2<MOPS. Conversely no differences in toxicity were observed when test pH was alkalinized using MOPS or NaOH. The different impacts of pH manipulation methods on Pb toxicity are likely due to different physiological stresses resulting from the respective methods; the physiological implications of each method are discussed. The results suggest that when studying the impacts of pH on metal toxicity it is important to properly replicate the ambient conditions of interest as artificial buffering using CO2 environments or organic buffers significantly affects the physiology of the test organisms above and beyond what is expected from pH alone. Thus, using CO2 and organic buffers overestimates the impact of acid pH on Pb toxicity